Of course, psychological factors are only some of many causes underlying the failure to respond to genocide. But the psychology is important and it has implications for policy that, so far, have not been addressed.

Briefly, the psychological explanation can be summarized as follows:

“The statistics of mass murder or genocide—no matter how large the numbers—do not convey the true meaning of such atrocities. The numbers fail to trigger the affective emotion or feeling required to motivate action. In other words, we know that genocide in Darfur is real, but we do not “feel” that reality. In fact, not only do we fail to grasp the gravity of the statistics, but the numbers themselves may actually hinder the psychological processes required to capture attention and create emotion.”

The broader message of this psychological explanation is that we cannot trust our quick, natural, intuitions that we rely upon heavily to tell us whether or not some moral transgression is occurring and to motivate us to respond. Rather, our moral intuitions fail us when the number of lives involved becomes large. Indeed, the research shows that the breakdown of compassion can be seen to begin when the number of needy persons goes from 1 to 2!

This psychological account has received widespread attention from radio and print media around the world, as well as from internet bloggers. Many appeared startled to see science confirm what they recognize as a shortcoming in their own feelings and responses to mass tragedies.

Yet, much to my surprise, no one has seriously thought about what I believe to be an important implication of the psychological analysis. The fact that we cannot trust our moral intuitions highlights the need to invoke our capacity for deliberate, rational thought, i.e. moral argument, to guide us in the face of genocide. Such moral deliberation led to the drafting in 1948 of the Genocide Convention, designed to prevent such crimes against humanity from ever happening again. Yet this convention has proven ineffective in numerous episodes of genocide that have occurred after World War II. Why is this the case?

Is it a failure of the Convention, or of the UN and the international signatories who pledged to uphold it? Does the Convention need fixing? Or, do we need new laws and institutions to compel us to respond properly when signs of genocide come to our attention? The psychological account shows the need for such questions to be taken seriously – now! But this is where my expertise, as a psychologist, leaves off, and I must hope that those of you with expertise in international law, human rights, and politics, will take up the challenge of curtailing mass murder and genocide in the 21st Century.